Photosensitive laminates have been used for years to create imageable patterns useful for etching of substrate materials. These photosensitive laminates comprise a photosensitive material which, upon selective exposure to light of an appropriate wavelength range, forms regions of two distinct types: regions which are easily removable by a developer liquid and regions which are not easily removable by the developer liquid. After developing with the developer liquid, these removable and non-removable regions then form void areas and mask areas in the photosensitive material. The developed photosensitive laminate can then be applied to a target surface and exposed to an etching material, such as a particulate abrasive. The void areas allow the particulate abrasive media to strike the target surface, while the mask areas protect the underlying target surface from the particulate abrasive.
The photosensitive materials used in the laminates can be selectively exposed to light using various methods, of which one common method is stacking a light-blocking stencil onto the laminate. The stencil contains a pattern corresponding to the portions of the laminate that are to be removed (in photo-negative applications), and thus should not be exposed to light. The stencil is held in place over the unexposed photosensitive laminate (such as under a transparent glass sheet and with a vacuum table) and then the stencil and laminate are exposed to light of the correct wavelength, intensity, and duration to react the exposed portions of the laminate. The stencil is subsequently removed and the laminate film developed. In this manner, high definition patterns can be transferred to the laminates. Thereafter, the laminate structure can be used for screen printing, abrasive etching, chemical etching, or other specific applications.
Although traditional methods of forming a pattern with a stencil placed on the photosensitive laminate are satisfactory for many applications, a need exists for improved materials and methods. In particular, a need exists for materials and methods that simplify the process of making imaged patterns in polymeric films and which do not require use of a stencil.